Electric power indicating switch



Sept. 9, 1952 L. N. BENNER 2,610,237

ELECTRIC POWER INDICATING SWITCH Filed Nov. 16, 1949 2 SHEETS--SHEET 2 [law/e mlor lo aljY-fleizrzer y m3 Patented Sept. 9, 1952 UNITED STATES PATENT orrlcs Lloyd N. Benner, Brunswick; Maine Application November 16, 1949, Serial No. 127,744 7 This invention relates to an electrical testing device for permanent attachment to a junction box,and in particular to a device for indicating the presence of electrical power at a switch box or breaker cabinet located on the premises of a consumer and connected to the main supply line of the premises. In the event that a lack. of current exists at some outlet on the consumers premises it is desirable to determine quickly whether the trouble results from a defect in the fuses or wiring of the consumers distribution system or from a failure of power on the main supply line, and thus whether the consumer should report the trouble to his electrician or to the power company. Especially in rural areas it is desirable that the power company be spared long and expensive service trips when the trouble results from a blown fuse which might be replaced locally.

So that such a device for use by a consumer will be reliable it should be rugged in construc tion and capable of simple operation. Since it is to be produced in great quantities for .general installation it should be simple in design, adapted for attachment to standard switch boxes and require a minimum of electrical wiring, and should be sufiiciently safe to receive the approval of the underwriters laboratories.

Objects of the present invention therefore are to provide a reliable testing device, which, is durable and capable of mass production and which may be safely and easily attached to standard equipment commonly installed on the premises of a power consumer. A specific object is to provide a testing device which may be easily mounted in the knock-out hole of a standard switch box.

In one aspect the invention involves the combination of a tubular sleeve which contains a pair of electrical contacts held apart by suitable resilient means, a contact closing member adapted to slide within the sleeve to move the contacts between open and closed condition, and a lamp within the sleeve. In one aspect of the invention a distinguishing feature comprises threaded portions of differentdiameters at the ends of the sleeve, the threaded portions being of proper size for insertion in a knock-out hole of one of two standard diameters. The sleeve may be secured in a knock-out hole and the contacts and lamp connected in series with the terminal of a switch box and the device may be operated to indicate the presence of electrical power at said terminals. In another aspect the sleeve is provided interiorly with 4 Claims. (Cl. 177-311) a portion of reduced diameter which provides an annularabutment opposed to the inner end of the sliding member and insulating discs are fitted in the sleeve to bear against the abutment and the inner end of the sliding member respectively, the discs being provided with contacts and held apart by a helical spring or other resilient means and capable of being closed on movement of the tubular member to complete a circuit between theenergized and grounded terminal of the switch box through a lamp mounted within the tubular sleeve thereby affording a simply constructed device for indicating the presence of electrical power at the terminals.

For the purpose of illustration a typical embodiment of the invention is illustrated in the accompanying drawing in which Fig. l is a side elevation of the testing device mounted on a switch box shown partly in section;

Fig. 2 is an end view of the device and switch box; 9

Fig. 3 is a section on line 3-3 of Fig. 2;

Fig. 4 is a wiring diagram showing the connection of the testing device to the switch box;

Figs. 5 and 6 are side elevations of modified devices; and r Fi '7 is a sectional view of the device shown in Fig. 6.

The embodiment of the testing devices illustrated in Figs. 1 to 4 includes an outer tubular casing I of conducting metal provided at its ends with threaded portions 2 and 3 for mountin the casin in a knock-out hole 4 or 4a in the wall 6' of a switch box 1. As shown in Fig. 3 a tubular sleeve 8 of translucent plastic slides in the bore 8 of the casing I. A hollow portion ll of reduced diameter extends outside the casing I through an opening [2 in a retaining screw capifi. The extended portion ll serves as a push button and as an enclosure for a neon lamp L. Adjacent the smaller threaded end 2 the bore of the casing l is reduced in diameter to provide an annular abutment I4 opposed to the inner end it of the sleeve 8. Insulating discs or plugs I1 and [8 are held respectively against the abutment l4 and the inner end is of the sleeve by a helical spring l9. tuberances 2| are fixed to the insulating plugs l1 and [8 to space the spring from the contacts 22. I-Iollow shanked rivets 22 which join the insulating and positioning discs are located centrally on the discs. The heads of the rivets 22 are opposed and act as contacts when brought together by operation of the push button por- Preferably positionin discs or protion II. The neon lamp L is heldin position within the translucent sleeve 8 by a soldered connection of one of the lamp lead wires-23 and the outer hollow rivet 22. The other lamp lead wire 23 is connected to a dropping resistor R from which a lead wire passes through the disc R8 at one side of the disc where it is turned to provide a lamp terminal (2!! which makes contact with the spring l9. An extension 24 of the op posite end of the sprin passes through theplug H and makes contact with the abutment I i of the casing I. An insulated wire 26 interconnects the inner rivet 22 with a switch box terminal (Fig. 4).

As shown in Fig. i the grounded main power line G is electrically connected to the switch box 1 and the junction box is grounded accordingto standard practice. The energized or potential carrying power line is connected to an insulated terminal E. A fuse F is interposed between the terminals E and the lines: to thelocal distribu tion cabinet. When contacts 22 areclosedcur= rent flows from terminal E-throughthecontacts;

through thelampi-Landthe-resistor R to the;

casing l, and thencethrough the walls of'the switch box 7 to the-groundedterminar G.

According to the einbodiment of Figs.

threaded portions 2 or 3hr sleeve 5 make'electrical contact the'wallsof the. groundedswitch box thus eliminatinga two-conductor. con

nection between thelamp and: the? terminals: This designis made feasibleby providing threaded portions 2 and Swith-a diameter slightly'less than that of two standardsized-knockeoutholes 3' and-4o; of half inch and. three-quarter inch diametersrespectively. Thus, the'device may-be secured in a knock out hole at eitherend at the smaller end 2=by means'ofanut" 27 (Fig. 1'), or

atthelarger end by means-of'a nutiit and-the retaining cap I3.

Inthe modified. embodiment shown in Figsb to 7 the stationary insulating plug 1m and the movable plug 18a areprovided with; telescoping walls 3.] and't Z; respectively which spacei the spring IS away-from the s contacts 22.. carried. by the plugs and provideadded;insulation between the spring and the contacts. A reces's 33 is pro.- vided'in the outer end of' the movablepiug; 18a to receive the dropping resistor R and the (leads fiiifromthe lampLto the resistorv and one 'contact rivet-22. Alea'dwii'e from the resistor passes from: recess ts'throughplug 18a, and-is turned to form a lamp terminal 2iicontactedfby the outer end 'of spring IS. The-other'en'd of the spring which bears against the stationaryplug Ila is expanded so that itmakes' an, electrical contact withthe bore!) of casingl. The casing i may be par-- tiallyenclosedby the cap IBhaving central opening 12 (Figs. 6' and?) or by a peripheralfiange' iSa (Fig. 5) turned in during manufacture;

In the embodiment shown inFigs-g5to'7" the plugs Na and liiidmay be inserted in the casing i in the position shown in Fig. '7 or in'reversed position, so that'thepush button H extends through the peripheral flange liia or the cap i3at the wider'end of the casing (Figs. 5 and 7), or throughthe reduced endof the casing'2 (Fig. 6). Thus the casing maybe mounted in the knock-out hole of a switch box to extend from the wall 8- of'the switch boxiFig. 5) or so. that it is substantially flush with-the wall. The location ofthe push button may be'selected by the manu-v iacturer-where the peripheral flange i3a of Fig. 5" is employed or by the user where therthreaded.

cap [3 is used. In either case the use of the re-' versible plugs allows a simple variation in assembly afiordi'ng a construction which is economical to manufacture and easy to use.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fallwithin the scope of the appended claims.

I claim: a

1. For attachment in amounting hole of a switch box or the like, an electric power indicating switch comprising a tubular casing carrying mounting means for securing one end of the casing in saidihole, an internal abutment forming a restricted opening at one end of the casing, means providing a second internal abutment and restricted opening; at the other end of the casing, a pair of blocks slidable in the casing, opposed contacts on said blocks, a spring urging the blocks respectively toward said abutments to hold said casing'mayybeattached either outside said.

mounting hole or substantially flush with. said hole and with the plunger disposed outside the 7 switch box.

2. For attachment in a mounting hole of a switch box or thelikean electric power indicating switch comprisinga tubular. casing carrying mounting means for securing one end of the casing in saidhole'; an internal abutment forming a restricted opening, atone end of the casing, means. providing a .secon'dint'ernal abutment .and restricted openingatthe other end ofthe casing, a pair of blocks slidable in the casing, opposed contacts disposed? centrally on said blocks, a spring .urging-theblocks respectively toward said abutments to hold said contacts apart, said spring havinga-coil .of. diameter to contact the inside of said casing, plunger means extending into the casing through one of said openings and operable to urge the blocks toward each other until their contacts meet, said-plunger means having a light transmitting push.- button portion. of smaller. di-

mension than either opening, lamp meanscon nectedto; the contactof one block, a conductor connected at. one endto-said lamp'and having its other end disposed between saidspring and said-one block, said'blocks being substantially of the same dimension transversely of theinside of said casing andhav-ing mutually telescoping wall members aroundxsaid contacts, whereby said switch may besassembled' with:said one-contact carrying block. and lamp selectively disposed adjacent either end opening and with said push button portion-extending through the selected end opening and said casing may be attached either; outside said mounting hole or substantially flush with said-hole: and with the plunger disposed outside the switch box, said' telescoping wall members insulating the-contacts from the spring;

3. For attachment in a mounting hole of a switch box or the like, an electric power indicating switch comprising a tubular casing carrying mounting means for securing one end of the cas ing in said hole, lamp means within the casing, a pair of spring-opened blocks carrying contacts for completing a circuit to the lamp, a plunger slidable in the casing and operable to close said contacts, said casing having a shoulder forming an internal abutment at said one end and means forming an internal abutment at the other end of the casing, said abutments confining said blocks and plunger within the casing. and said plunger having a light transmitting push button portion dimensioned to extend outside the casing past either of said abutment/s so that the switch may be assembled with the plunger extending past either one of the abutments and with the contact blocks against the other abutment, whereby the casing may be mounted either 6 outside said switch box mounting hole or substantially flush with said hole and with the plunger extending outside the switch box.

4. The switch according to claim 1 characterizedin that said spring is in helical form around said contacts, and said blocks carry mutually telescoping tubular portions disposed between said spring and said contacts to insulate said contacts from said spring.

LLOYD N. BENNER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,424,573 Marco July 29, 1947 2,424,574 Marco July 29, 1947 

